Class Notes (836,169)
Canada (509,675)
Anthropology (1,673)
ANT208H1 (76)
Dan Sellen (28)

ANT208 March 15 Lecture

8 Pages
Unlock Document

Dan Sellen

Reproduction, Part 2 Lecture Outline - Sex determination + sex differences - Reproductive Strategies o Sexual selection: mate choice + parenting o Sex differences: development + life history o Ecological variation: secular changes - Reproductive health, by gender o Birthing, breastfeeding o Sexual health Sex Determination Biological sex + gender = a function of phenotype Product of genetics x environment  single informational unit Ordered Process: - Chromosomal sex (fertilization) - Gonadal sex (early fetal development) - Phenotypic sex (accessory sex structures) o Chromosomal sex usually agrees with phenotypic sex o This is determined after puberty (body proportions, voice deepening in males, breast development in females = adult sex phenotypic development) Epigenetic influences - Modulate gene expression during lifespan o Early development has large effects on long term influence (just like nutrition examples)  Meaning that early exposures can influence sex development - Early development has long-term effects, larger influence - Age, education, experience, conditioning Explaining sex differences Generalized differences between male and female - Bodies - Health risk and vulnerabilities … support predictions of evolutionary theory Sexual selection theory Predicts that there would’ve been many species with an evolutionary history of gender specific selection forces that lead to gender-specific lifetime investment which may lead to conflicting needs - Gender-specific lifetime investment in o Mating effort o Reproductive effort - Gender-specific intensity of intra-sexual competition for mates Important to consider the tradeoffs between time, resources and risk spent finding a mate VS. finding a good mate (or many mates) that will help to produce good/healthy offspring There’s a tendency on male mammals to put a lot of effort into mating (production of sperm – a way to secure fertilization, male-male competition, etc) Reproductive Strategies Parental Care Mating System Fish Male only Polygamy/promiscuity - Often take fertilized eggs and put them in their mouth  good way to protect their offspring Bird Both male and female Monogamous - Fitness of offspring is largely dependent on how fast the parents can bring food to their offspring - Better for male reproductive fitness if he stays around to bring food to offspring VS. spending their time, energy and resources to find other mates Mammals Mostly female Polygyny - Males don’t seem to do anything for offspring - Most of these species – males, if they can out compete other males, will find other mates - Female mammals don’t do this b/c they invest a lot of their own resources and effort in caring for the offspring - And the fact that males don’t help take care of offspring makes it even more difficult for female/decreases female fitness further - Compensate by reducing mating effort - Males are limited by the number of females that haven’t mated Ecology + phylogeny modify how cost of reproduction affects parental investment ….. Secular trend to fewer pregnancies - Contraception o Drives a lot of difference between societies o Access to birth control - Affects ovulationary cycles - Women’s work roles - Relative value of children o Juvenile production vs cost Fecundity, fecundability, proximate determinants of fertility There are many populations with high fertility - Hidden demand for contraception that’s not being met - Education and work – people (especially women) begin to value different things - Shift in social values + opportunities - Social things > biological things There’s a lot of theories to explain demographic differences - Key insight: if you move from thinking about # of offspring vs. quality of offspring  offspring quality varies in value and is constructed across various societies How have modern environments created health problems? - Sperm production o Environmental effects? o Links between testosterone and male cancers (e.g., prostate cancer?)  There’s been lots of changes in male life histories  Problems with testosterone  is associated with lowered survival among male animals  Suppresses immune response  Testosterone  makes your body build muscle, high metabolic rates, promotes riskier behavior  So when you produce this something has to tradeoff  in this case, it’s the immune system  Men who spend more time with their children seem to have a reduction in their testosterone levels from before (changes in hormonal profile b/c of social behavior) Lifetime hormone exposure - Disparities in cancers? - Links to other outcomes? o High levels of ovarian hormones  long flows, more problems with menstruation, more PMR and cycle related mood swings, greater risk of osteoporosis, etc Aging - Age-related change in adulthood o Reproduction + diet + health + senescence (loss of function) are linked o The factors aforementioned are related o Key conceptual idea: biomedicine has treated aging as losing function – as a pathology  Evolutionary perspective: mayb
More Less

Related notes for ANT208H1

Log In


Join OneClass

Access over 10 million pages of study
documents for 1.3 million courses.

Sign up

Join to view


By registering, I agree to the Terms and Privacy Policies
Already have an account?
Just a few more details

So we can recommend you notes for your school.

Reset Password

Please enter below the email address you registered with and we will send you a link to reset your password.

Add your courses

Get notes from the top students in your class.